The invention concerns a rotary piston machine as defined by the elements of the independent claim. A rotory piston machine for use in a pump, a compressor, a turbine or motor must exhibit properties which allow its design to be precisely calculated. In dependence on the application and the fluid dynamic properties of the medium being transported or pumped, the design of the power and blocking components must be effected in such a way that effective transport performance is obtained. Moreover, the production of these components must be done by means of a tool whose proper design is important in order to minimise production costs.
In a conventional rotary piston machine (DE P 42 41 320.6; DE G 92 18 694.7; PCT/DE 92/01025), all lines of the cycloid component and the central component extending transverse to and defining the operating direction pass through the point of intersection of the axes of rotation. This limits the expansion and compression behavior of the working chambers and therefore adaptation of the rotary piston machine to various working media and fields of application. FR 838,270,GB 1,099,085 and DE 2639760 all disclose rotory piston machines having a power component and a blocking component. The power component and blocking component teeth mutually engage and are configured to have shapes generally of a conical section type (i.e. conical, circular, parabolic, ellipsoidal, or hyperbolic). These teeth shapes of prior art have the disadvantage that a plurality of contact lines occur between the blocking and power components per chamber during operation. This causes reduced efficiency in fluid transport through the chambers and complicates calculation of the pressure and flow properties of the fluid during the course of operation.
In view of these disadvantages of prior art it is the underlying purpose of the present invention to design a rotory piston machine for a pump, a compressor, a turbine or a motor having a structure which facilitates precise calculation of the flow properties of the medium in the chambers during operation in dependence on the fluid dynamic properties of that medium and which permits efficient design of a tool for producing the power and blocking components.
This purpose is achieved in accordance with the invention with a rotory piston machine having a power component whose teeth are shaped using a cycloid generator. The cycloid shape not only allows precise calculation of the properties of the rotory piston machine but also produces one line of contact per chamber between the power and blocking components which propagates monotonically through the chamber during the course of operation thereby providing efficient operation of the pump and precise determination of the action of the pump on the transport response of the fluid. The intake and output behavior of the working chambers is determined by the phase shift, to thereby reduce undesired back-flow or mixing between the intake and output working media.
According to an advantageous embodiment of the invention, the phase shift from the inner to the outer diameter is at least 360xc2x0 such that the working chamber is closed off from the surroundings at least at one angular position of the first or second component.
According to a further advantageous embodiment of the invention, the amplitudes of the cycloids forming the operating surface of the cycloid component differ from one another. This allows additional freedom in designing the behavior of the working chambers.
According to a further advantageous embodiment of the invention, the working chambers are separated by a positive fit between the sides and tops of the opposing component teeth. Due to the different number of teeth, the tooth tops of the control component advance along the sides of the cycloid component teeth to essentially eliminate fluid back-flow. In addition, the control component can thereby be driven by the cycloids.
According to a further advantageous embodiment of the invention, there is no positive fit between the cycloids forming the operating surfaces of the cycloid component and the control component. The machine is then a flow machine whose characteristics are defined by the impulse and mass of the working medium. Moreover, sensitive media having characteristics impaired by compression may also be used as the working medium.
According to a further advantageous embodiment of the invention, the control channel for input of the working medium is disposed at the outer diameter, and the control channel for output of the working medium is disposed on the inner diameter of the tooth structures. During turbine or motor operation, the impulse and mass forces generated by the working medium are aligned with the direction of displacement of the working chamber. This reduces leakage losses and improves efficiency.
According to a further advantageous embodiment of the invention, the working positions of the axes of rotation of the components can be changed independently of one another. In accordance with the invention, additional pairs of toothed disk structures can be incorporated. At least one of the components has toothed gearing on its back side which cooperate with an additional rotating component having single or double teeth. This requires a radial seal between the enclosing casing and these rotating components. Drive and output may be effected in a conventional manner using shafts or toothed wheels connected to the rotating components or disposed thereon and cooperating with additional drive or output means. By changing the working positions of the rotary axes, the volume change in one component of the rotary piston machine can be advanced or retarded with respect to the other to permit graduated operation through connection of the working chambers or for mixing.
According to an advantageous embodiment of the invention, there are two cycloid or control components and the additional part is disposed between the doubled components in the form of a ring with toothed surfaces or cycloid operating surfaces. According to a further embodiment, at least two working chambers, on opposite sides of the ring, can be connected to one another. This creates e.g. a double pump or power machine, in which a control component, with teeth on both sides, is disposed between two absolutely synchronously rotating cycloid components with a number of teeth differing by one tooth from the number of teeth on the doubled components. This control component may comprise a drive or output device in dependence on whether it is a pump or a motor. Alternatively, the drive and/or output may be effected via the doubled cycloid components. The casing may serve as a stator supporting both driven cycloid components at corresponding working angles between which the control component, having sides with a number of teeth differing by one tooth, freely rotates.
According to a further advantageous embodiment of the invention, the casing or the control component has appropriate channels for the input or output of the working media, which may be optionally controlled during rotation. This precludes additional valves and also effects rinsing in the centrifugal direction.
According to a further preferred embodiment of the invention, the radial circumference of the components is spherical, and the components are guided on a corresponding spherical inner surface of the casing in a radially sealing manner. This spherical guidance permits change in the working position without creating additional sealing problems. This outer or inner radially sealing, spherical working chamber wall may be connected to the control or cycloid components and may rotate therewith to center the components with respect to each other.
In a further advantageous embodiment of the invention, the rotary piston machine is a compressor with control independent of the rotational speed effected, in particular, by changing the phase shift of the two rotating parts relative to the channels of the working media. In addition to the advantageously stable centrifugal force dependence of the moving components, the small size, and large power, the phase shift permits continuous control of the compression ratio, independent of the rotational speed. Such a compressor is particularly suitable for charging combustion engines, since they have high, widely varying rotational speeds, since the mass of the charger should be as small as possible (in particular the driven rotating masses), and since the power must be controlled independently of the rotational speed. Since several pairs of working chambers can operate in a phase-shifted manner, the valve-less control in the direction of flow (no inversion of flow) and the very high sealing quality of the working chambers, permit the inventive compressors to be used in pressure ranges currently accessible to piston machines only.
In a further advantageous embodiment of the invention, the rotary piston machine is a hydrostatic element used as a pump, motor or transmission. These applications are advantageously influenced by the extremely favorable relationship between the size and volume exchange. The simple kinematics, the rotational speed stability of the structure and the very large rinsing channel cross-sections ensure that these machines are also suitable for the highest of rotational speeds. The inner flow resistance of the machine according to the invention is extremely low. If it is used as a pump, the high inherent stability of the components has advantageous effects. Wear is limited to rubbing between the movable components. In addition, the machine is suitable for the highest working pressures. If it is used as a hydraulic motor the same advantages obtain, in particular, the small accelerated masses, the good starting behavior, and the high volume efficiency. The low construction volume and the compact manner in which the pump and the hydraulic motor can be connected is particularly advantageous for use as a hydrostatic transmission.
In a further advantageous embodiment of the invention, the rotary piston machine is a power machine or refrigerator, in particular, operating according to the Stirling principle, wherein the cooperating working chambers are phase-shifted by 90xc2x0. Two rotating cycloid components cooperate with a rotating control component to form operating chamber pairs which are each phase-shifted by 90xc2x0. One chamber is heated and the other cooled, and a regenerator is integrated into the control component. In accordance with the invention, there is no component exchange between the warm and cool regions. The walls of the cold and the warm working chambers are insulated from one another despite their close spatial proximity. An advantageous convection surface/working chamber volume ratio can be achieved due to the high inherent stability of the components forming the working chamber. One of the rotating components may be a linear generator driver for a Stirling motor or a linear motor for a Stirling refrigerator. The machine can therefore be hermetically sealed and designed for very high loading pressure with low working gas leakage loss. The phase shift defining the performance of the Stirling motor can be easily realized in this embodiment. In any event, the amount of transported heat can be regulated in such a refrigerator, irrespective of the rotational speed.
Further advantages and advantageous embodiments of the invention can be extracted from the following description, the drawing and the claims.
Embodiments of the invention are shown in the drawing and further described below.